Tall oil-melamine reaction product



Patented Dec. 4, 1951 TALL OIL-MELAMINE REACTION PRODUCT AND PROCESS Philip C. Hamm, Kansas City, Mo., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application November 15, 1949, Serial No. 127,507

I 2 Claims. 1

The present invention relates to the reaction of tall oil anhydride with melamine to produce mixed N,N,N"-triacylmelamines.

The N,N',N"-triacylmelamines having the structural formula:

N H o RLIL C dial o la wherein R is an alkyl group of from 4 to 17 carbon atoms, have been described and claimed in the copending application of W. S. Emerson and T. M. Patrick, Jr., Serial Number 712,738, filed November 27, 1946, now U. S. Patent No. 2,507,700.

It is the principal object of this invention to produce N,N',N"-tri tall oil melamine by the reaction of substantially 3 moles of tall oil anhydride with one mole of melamine at from about 160 to 230 C. for from about 15 to about 60 minutes, in a substantially water-free system. This product was found to be useful in water repellant formulations for the treatment of wood products, such as lumber, plywood, and the like.

It has now been found that N,N',N"-triacylmelamines can be prepared from a mixture of rosin acids and unsaturated and saturated fatty acids known as tall oil. Tall oil is subject to considerable variation in. composition being in part dependent on the species of wood processed, the season of the year that the tree was felled, the age of the tree, the storage life of the wood, the procedure for processing the chips and converting the black liquor into tall oil, etc. Thus, the average analysis of tall oil from fifteen mills ranged from 36 to 54 percent fatty acids, 38 to 58 percent rosin acids, and 6 to 18 percent unsaponifiable. The fatty acids of tall oil are primarily unsaturated fatty acids, principally oleic and linoleic in substantially equal amounts, with a small content of saturated fatty acids, predominantly palmitic. Abietic acid is the predominant rosin acid of tall oil. While crude tall oil is applicable, it is preferred that a refined tall oil be employed to improve the color and odor of the product.

In general primary arylamines may be acylated with acyl halides, fatty acid anhydrides, esters of fatty acids, and fatty acids and it might thereby be expected that heterocycllc primary amines of 1,3,5-triazine, for example melamine, would be subject to similar reactions. Repeated at- 2 tempts were made to acylate melamine with other than fatty acid anhydrides without success. This appears unexpected, particularly since the acyl chlorides are regarded to react vigorously with primary amines. This unique ability of the acid anhydrides to react with melamine is unexpected and unexplained at the present time. The above failure of acylation of melamine by prior art 'acylation methods would indicate that this reaction is unpredictable and it would not necessarily be expected that acylation of melamine was possible by replacing a relatively pure anhydride of fatty acid by the anhydrides of a variable natural mixture such as tall 011.

The following examples are illustrative of the invention:

Example 1 2RCOOH CHsCO) 2O- (RCO) 2O+2CH3COOH The pressure on the system was then reduced to 50 mm. of mercury while continuing the fractionation. The excess acetic anhydride wasthen fractionated oil at a pot temperature of about 100 C. and a head temperature of about 66 to 67 C. until the bulk of the excess acetic anhydride was collected. Then the pot temperature was slowly raised to 215 C. after which the pressure was gradually reduced to 1'7 mm. of mercury while holding at this temperature and held under these conditions for about one-half hour to remove the last traces of acetic anhydride. The mixed product of tall oil anhydrides, obtained as the distillation residue, was employed in the following examples.

' Example 2 riod. The reaction mixture was held at to I 3 200 C. for 3 minutes. was allowed cool forming a semi-solid mass at room temperature. a This material was warmed slightly to fluidity and was poured in a thin stream into 500 ml. oi acetone .with vigorous stirring, centrifuged, and the acetone containing the Example 3 A 10.1 gram sample (0.08 mole) of melamine and 1'12 grams (approximately 0.296 mole) of tall oil anhydride from Example 1 were introduced into a 500-ml. three-necked round bottom flask fitted with a stirrer, thermometer and vent tube containing a desiccant to protect the system from atmospheric moisture. The flask was supported by an electric heating mantle. The mixture was rapidly brought up to 200 C. in 15 minutes while vigorously stirring, then the reaction mixture was held at from about 200 to about 210 C. for 30 minutes while continuing to stir. The reaction mixture was cooled until only slightly warm at which time it was poured slowly in a thin stream into about 500 ml. of ice cold acetone with vigorous stirring and the finely divided, light tan, waxy precipitate was recovered by filtration. The product was reslurried and filtered twice with 400 and 250ml. of ice cold acetone. respectively, then dried in a vacuum desiccator. The N.N',N"-tri tall oil melamine product was recovered in a slightly greater yield than shown in Example 2.

It is seen that the approximately 108 percent excess of tall oil anhydride of Example 2 is not more advantageous than the 23 percent excess of Example 3 the yields being substantially equiv-- alent. In commercial production it is preferred that substantially 3 moles of tall oil anhydride be employed per mole of melamine or a slight excess of the tall oil anhydi'ide can be employed. This procedure will require less purification than when a large excess of tall oil anhydride is employed and will thereby reduce the handling losses. Also somewhat less than 3 moles of tall oil anhydride can be employed per mole of melamine, but the resultant product has slightly lower water repellency properties.

By "mole of tall oil is meant the average molecular weight of the components of tall oil and the anhydride would thus indicate the usual removal of a mole of water from two moles of tall oil acids (two mole equivalent carboxyl groups) to yield one mole of the anhydride. Tall oil anhydride is thus synonymous with anhydr of tall oil acids.

Then the amber solution The reaction can be employed over the temperature range of from about to about 230 C. but the range of from about to about 210 C. is preferred. In generaL'as is well-known, for chemical reactions, the higher temperatures will require less reaction time; thus, the effective reaction time can be from about 15 to about 60.

minutes.

Other solvents than acetone can be employed. as for example methanol, ethanol. and ethyl acetate to remove the excess unreacted anhydride and by-product acids. When substantially equivalent reactants to form the N,N',N"-tri tall oil melamine are employed, the amount of solvent required will be held to a minimum.

It was found that relatively crude N,N',N"-

tri tall oil melamine had about 80 percent the water repellent eifectlveness of purified N,N',N"-

trioleoylmelamine as measured by the smallwater test method with similar formulations containing both 0.5 and 1.0 percent of the above materials. It is surprising that a mixture embracing a rather wide variation in composition can be employed with substantially equivalent results to materials produced from a substantial pure compound.

It was found that N,N',N"-triproplonylmelamine and N,N,N"-tristearoylmelamine could not be satisfactorily formulated as water repellent wood sealer compositions. This indicates that the unsaturated N,N',N"-triacylmelami are to be preferred in this respect.

' I claim:

1. N,N',N"-tri tall oil melamine, a tion having the structure composi- PHILIP C. HAMIJ.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Country Date Great Britain 1931 OTHER REFERENCES Number Sidgwiclr: Organic Chemistry of Nitrogen,

Oxford Press, 1937, p. 138. 

1. N,N'',N''''-TRI TALL OIL MELAMINE, A COMPOSITION HAVING THE STRUCTURE 